1. Field of the Invention
The present invention relates to an image reading apparatus and an information processing apparatus using the image reading apparatus, and more particularly to an image reading apparatus having a light source with a light guide (hereinafter called a "light guide unit") for guiding light to an image reading surface and a base unit for photoelectrically converting light reflected from the image reading surface into an electrical signal.
2. Related Background Art
Conventionally, an image reading apparatus having the structure such as shown in FIGS. 17 and 18 has been used with an information processing apparatus such as a facsimile apparatus and an electronic copying machine. FIG. 17 is a cross sectional view of a conventional image reading apparatus, and FIG. 18 is a broken perspective view of the image reading apparatus.
Referring to FIGS. 17 and 18, reference numeral 21 represents a sensor array having a length corresponding to that of an original to be read, reference numeral 22 represents a sensor array board on which the sensor array 21 is mounted, reference numeral 23 represents a focussing element for focussing light reflected from an original surface onto a light reception surface of the sensor array 21, reference numeral 25 represents a transparent member in contact with the original surface, and reference numeral 24 represents a light guide for guiding light radiated from a light source 27 such as LED disposed on the side at one end of the light guide unit toward the original surface. Reference numeral 26 represents a frame on which, as shown in FIG. 18, the focussing element 23, light source 27 and light guide 24 are mounted and thereafter the transparent member 25 is mounted on one side of the frame 26 and the sensor array board 22 is mounted on the other side thereof.
In the image reading apparatus constructed as above, in order to make light guided by the light guide unit 24 and reflected from the original surface be correctly incident via the focussing element 23 upon the light reception surface of the sensor array 21, it is necessary to mount the sensor array board 22, focussing element 23, light projector 24 and the like with high precision.
With the image reading apparatus constructed as above, however, a mount precision of each component varies also with a precision of the frame 26 itself on which each component is mounted. It has been desired therefore to form the frame 26 with high work precision of dimensions and suppress variations of dimensions.